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#![feature(core_intrinsics)] // for `volatile_set_memory`
#[repr(C)]
#[derive(Copy, Clone)]
struct Foo {
a: u64,
b: u64,
c: u64,
}
fn main() {
const LENGTH: usize = 10;
let mut v: [u64; LENGTH] = [0; LENGTH];
for idx in 0..LENGTH {
assert_eq!(v[idx], 0);
}
unsafe {
let p = v.as_mut_ptr();
::std::ptr::write_bytes(p, 0xab, LENGTH);
}
for idx in 0..LENGTH {
assert_eq!(v[idx], 0xabababababababab);
}
// -----
let mut w: [Foo; LENGTH] = [Foo { a: 0, b: 0, c: 0 }; LENGTH];
for idx in 0..LENGTH {
assert_eq!(w[idx].a, 0);
assert_eq!(w[idx].b, 0);
assert_eq!(w[idx].c, 0);
}
unsafe {
let p = w.as_mut_ptr();
::std::ptr::write_bytes(p, 0xcd, LENGTH);
}
for idx in 0..LENGTH {
assert_eq!(w[idx].a, 0xcdcdcdcdcdcdcdcd);
assert_eq!(w[idx].b, 0xcdcdcdcdcdcdcdcd);
assert_eq!(w[idx].c, 0xcdcdcdcdcdcdcdcd);
}
// -----
// `std::intrinsics::volatile_set_memory` should behave identically
let mut v: [u64; LENGTH] = [0; LENGTH];
for idx in 0..LENGTH {
assert_eq!(v[idx], 0);
}
unsafe {
let p = v.as_mut_ptr();
::std::intrinsics::volatile_set_memory(p, 0xab, LENGTH);
}
for idx in 0..LENGTH {
assert_eq!(v[idx], 0xabababababababab);
}
// -----
let mut w: [Foo; LENGTH] = [Foo { a: 0, b: 0, c: 0 }; LENGTH];
for idx in 0..LENGTH {
assert_eq!(w[idx].a, 0);
assert_eq!(w[idx].b, 0);
assert_eq!(w[idx].c, 0);
}
unsafe {
let p = w.as_mut_ptr();
::std::intrinsics::volatile_set_memory(p, 0xcd, LENGTH);
}
for idx in 0..LENGTH {
assert_eq!(w[idx].a, 0xcdcdcdcdcdcdcdcd);
assert_eq!(w[idx].b, 0xcdcdcdcdcdcdcdcd);
assert_eq!(w[idx].c, 0xcdcdcdcdcdcdcdcd);
}
}
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